Process for the removal of hydrocarbonaceous compounds from an aqueous stream and hydrogenating these compounds

ABSTRACT

A process for the removal of trace quantities of hydrocarbonaceous compounds from an aqueous stream which comprise the steps of: (a) contacting the aqueous stream with an adsorbent to remove trace quantities of hydrocarbonaceous compounds from the aqueous stream to provide an aqueous stream having a reduced concentration of hydrocarbonaceous compounds; (b) contacting spent adsorbent which has accumulated the hydrocarbonaceous compounds from the aqueous stream with an elution solvent to remove the hydrocarbonaceous compounds from the spent adsorbent thereby regenerating the adsorbent; (c) contacting the elution solvent in admixture with the hydrocarbonaceous compounds which were removed from the spent adsorbent in step (b) in the presence of hydrogen with a hydrogenation catalyst in a hydrotreating reaction zone; (d) contacting the hydrotreating reaction zone effluent with an aqueous scrubbing solution; and (e) introducing a resulting admixture of the reaction zone effluent and the aqueous scrubbing solution into a separation zone to provide a hydrotreated elution solvent and a spent aqueous stream.

BACKGROUND OF THE INVENTION

The field of art to which this invention pertains is the removal oftrace quantities of hydrocarbonaceous compounds from an aqueous stream.More particularly, the invention relates to the removal of tracequantities of hydrocarbonaceous compounds which are hazardous orotherwise obnoxious. More specifically, the invention relates to aprocess for the removal of trace quantities of hydrocarbonaceouscompounds from an aqueous stream which comprises the steps of: (a)contacting the aqueous stream with an adsorbent to remove tracequantities of hydrocarbonaceous compounds from the aqueous stream toprovide an aqueous stream having a reduced concentration ofhydrocarbonaceous compounds; (b) contacting spent adsorbent which hasaccumulated the hydrocarbonaceous compounds from the aqueous stream withan elution solvent to remove the hydrocarbonaceous compounds from thespent adsorbent thereby regenerating the adsorbent; (c) contacting theelution solvent in admixture with the hydrocarbonaceous compounds whichwere removed from the spent adsorbent in step (b) in the presence ofhydrogen with a hydrogenation catalyst in a hydrotreating reaction zone;(d) contacting the hydrotreating reaction zone effluent with an aqueousscrubbing solution; and (e) introducing a resulting admixture of thereaction zone effluent and the aqueous scrubbing solution into aseparation zone to provide a hydrotreated elution solvent and a spentaqueous stream.

INFORMATION DISCLOSURE

In U.S. Pat. No. 3,919,398 (Davis), a method is disclosed for recoveringbromine as hydrogen bromide from aromatic bromides. The method involvesreacting the aromatic bromide with hydrogen at a temperature within therange from about 200° to about 600° C. in the presence of a palladiumactivated catalyst.

In U.S. Pat. No. 3,892,818 (Scharfe et al), a method is disclosed forthe conversion of hydrocarbon chlorides in the presence of hydrogen tohydrocarbons and hydrogen chloride wherein the process takes place in agaseous phase and in the presence of a rhodium-containing catalyst.

BRIEF SUMMARY OF THE INVENTION

The invention provides a process for the removal of trace quantities ofhydrocarbonaceous compounds from an aqueous stream by contacting theaqueous stream with an adsorbent to remove trace quantities ofhydrocarbonaceous compounds from the aqueous stream and whereby thespent adsorbent is regenerated by removal of accumulatedhydrocarbonaceous compounds from the adsorbent by means of an elutionsolvent and subsequent processing of these hydrocarbonaceous compoundsin a hydrotreating reaction zone. The present invention alsocontemplates the recycle of hydrotreated elution solvent to a spentadsorbent for removal of hydrocarbonaceous compounds.

One broad embodiment of the invention may be characterized as a processfor the removal of trace quantities of hydrocarbonaceous compounds froman aqueous stream which comprises the steps of: (a) contacting theaqueous stream with an adsorbent to remove trace quantities ofhydrocarbonaceous compounds from the aqueous stream to provide anaqueous stream having a reduced concentration of hydrocarbonaceouscompounds; (b) contacting spent adsorbent which has accumulated thehydrocarbonaceous compounds from the aqueous stream with an elutionsolvent to remove the hydrocarbonaceous compounds from the spentadsorbent thereby regenerating the adsorbent; (c) contacting the elutionsolvent in admixture with the hydrocarbonaceous compounds which wereremoved from the spent adsorbent in step (b) in the presence of hydrogenwith a hydrogenation catalyst in a hydrotreating reaction zone; (d)contacting the hydrotreating reaction zone effluent with an aqueousscrubbing solution; and (e) introducing a resulting admixture of thereaction zone effluent and the aqueous scrubbing solution into aseparation zone to provide a hydrotreated elution solvent and a spentaqueous stream.

Another embodiment of the invention may be characterized as a processfor the removal of trace quantities of hydrocarbonaceous compounds froman aqueous stream which comprises the steps of: (a) contacting theaqueous stream with an adsorbent to remove trace quantities ofhydrocarbonaceous compounds from the aqueous stream to provide anaqueous stream having a reduced concentration of hydrocarbonaceouscompounds; (b) contacting spent adsorbent which has accumulated thehydrocarbonaceous compounds from the aqueous stream with an elutionsolvent to remove the hydrocarbonaceous compounds from the spentadsorbent thereby regenerating the adsorbent; (c) contacting the elutionsolvent in admixture with the hydrocarbonaceous compounds which wereremoved from the spent adsorbent in step (b) in the presence of hydrogenwith a hydrogenation catalyst in a hydrotreating reaction zone; (d)contacting the hydrotreating reaction zone effluent with an aqueousscrubbing solution; (e) introducing a resulting admixture of thereaction zone effluent and the aqueous scrubbing solution into aseparation zone to provide a hydrotreated elution solvent and a spentaqueous stream; and (f) recycling at least a portion of the hydrotreatedelution solvent from step (e) to provide at least a portion of theelution solvent utilized in step (b).

Other embodiments of the subject invention encompass further detailssuch as potential hydrocarbonaceous compound contaminants, aqueousscrubbing solutions, hydrotreating catalysts, adsorbents, elutionsolvents and operating conditions, all of which are hereinafterdisclosed in the following discussion of each of these facets of theinvention.

BRIEF DESCRIPTION OF THE DRAWING

The drawing is a simplified process flow diagram of a preferredembodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

There is a steadily increasing demand for technology which is capable ofeliminating trace quantities of hydrocarbonaceous compounds from aqueousstreams such as waste water and potable water, for example. Once anorganic phase is decanted from a water phase, the remaining water maypotentially contain trace quantities of organic compounds such ashydrocarbonaceous compounds for example. Before waste water can bedischarged into the environment, these trace quantities ofhydrocarbonaceous compounds must be reduced or eliminated. In the eventthat these trace hydrocarbonaceous compounds are toxic, carcinogenic orotherwise obnoxious, it is preferred that the hydrocarbonaceouscompounds not only be removed from the aqueous phase but converted intoless noxious compounds. Therefore, those skilled in the art have soughtto find feasible techniques to remove trace amounts of hydrocarbonaceouscompounds from an aqueous phase. Although simple in concept,conventional liquid-liquid extraction often is not practical for theremoval of hydrocarbonaceous compound contaminants at theparts-per-million level or even lower concentrations.

The present invention provides an improved process for the removal oftrace quantities of hydrocarbonaceous compounds from an aqueous stream.A wide variety of hydrocarbonaceous compounds are to be consideredcandidates for removal from an aqueous stream in accordance with theprocess of the present invention. Examples of compounds which aresuitable for treatment by the process of the present invention arehalogenated hydrocarbons. Certain halogenated hydrocarbons havingdemonstrated or potential toxicity include but are not limited tokepone, halogenated biphenyls, halogenated cyclodienes, such as aldrin,dieldrin, and hexachlorocyclopentadienes, dibromochloropropane,halogenated phthalic anhydrides, such as polybromophthalicanhydride,tetrachloroethylene, polychlorodioxins such as tetrachlorodibenzodioxin,halogenated organic phosphates such as 2,2 dichlorovinyldimethylphosphate. Additional examples of compounds which are suitable fortreatment include organometallic compounds and especially those whichcontain metals such as lead, mercury, cadmium, cobalt, arsenic,vanadium, and chromium. Contaminating hydrocarbonaceous compounds maycomprise sulfur, oxygen, metal or nitrogen components. In accordancewith the present invention, generally any hydrocarbonaceous compound maybe removed from an aqueous stream. It is preferred that the tracequantities of hydrocarbonaceous compounds are present in the aqueousstream in an amount less than about 10,000 PPM and more preferably in anamount less than about 5,000 PPM.

In accordance with the subject invention, an aqueous stream containingtrace quantities of hydrocarbonaceous compounds is contacted with asuitable adsorbent which selectively retains the trace hydrocarbonaceouscompounds and produces an aqueous stream with a reduced concentration ofhydrocarbonaceous compounds. Suitable adsorbents may be selected frommaterials which exhibit the primary requirement of hydrocarbonaceouscompound selectivity and which are otherwise convenient to use. Suitableadsorbents include, for example, molecular sieves, amorphoussilica-alumina gel, silica gel, activated carbon, activated alumina andclays. Of course, it is recognized that for a given case, a particularadsorbent may give better results than others.

The selected adsorbent is contacted with an aqueous stream containingtrace quantities of hydrocarbonaceous compounds in an adsorption zone.The adsorbent may be installed in the adsorption zone in any suitablemanner. A preferred method for the installation of the adsorbent is in afixed bed arrangement. The adsorbent may be installed in one or morevessels and in either series or parallel flow. The flow of an aqueousstream through the adsorption zone is preferably performed in a parallelmanner so that when one of the adsorbent beds or chambers is spent bythe accumulation of hydrocarbonaceous compounds thereon, the spentadsorbent zone may be bypassed while continuing uninterrupted operationthrough the parallel adsorbent zone.

During adsorbtion, the adsorption zone is preferably maintained at apressure from about atmospheric to about 1500 psig (10342 k Pa gauge), atemperature from about 32° F., (0° C.) to about 300° F. (149° C.) and aliquid hourly space velocity from about 0.1 hr⁻¹ to about 500 hr⁻¹. Theflow of the aqueous stream containing trace quantities ofhydrocarbonaceous compounds through the adsorption zone may be conductedin an upflow, downflow or radial flow manner. The temperature andpressure of the adsorption zone are preferably selected to maintain theaqueous stream in the liquid phase. As used herein, the term"essentially hydrocarbon-free" connotes a hydrocarbonaceous compoundconcentration of less than about 10 PPM.

The spent zone of adsorbent is regenerated by isolating the spentadsorption zone and contacting the adsorbent with an elution solvent toremove the hydrocarbonaceous compounds thereby regenerating theadsorbent. In general, an elution solvent is utilized which possesses ahigh solvent selectivity towards the hydrocarbonaceous compoundsadsorbed on the adsorbent and which has no deleterious effect on theadsorbent. Preferred elution solvents comprise naphtha, kerosene, dieselfuel, gas oil or mixtures thereof. During regeneration of the adsorbent,the adsorption zone is preferably maintained at a pressure from aboutatmospheric to about 1500 psig (10,342 k Pa gauge), and a temperaturefrom about 32° F. (0° C.) to about 300° F. (149° C.). The flow of theelution solvent through the adsorption zone during regeneration thereofmay be conducted in an upflow, downflow or radial flow manner. Theelution solvent during the regeneration of adsorbent may be present in aliquid phase or a gas-liquid mixed phase.

The resulting elution solvent containing the hydrocarbonaceous compoundsis introduced into a hydrotreating or hydrogenation zone and iscontacted with a hydrogen-rich gaseous phase and a hydrogenationcatalyst. The catalytic hydrogenation zone may contain a fixed, ebulatedor fluidized catalyst bed. This reaction zone is preferably maintainedunder an imposed pressure from about 100 psig (689 k Pa gauge) to about2000 psig (13,790 k Pa gauge) and more preferably under a pressure fromabout 200 psig (1379 k Pa gauge) to about 1800 psig (12,411 k Pa gauge).Suitably, such reaction is conducted with a maximum catalyst bedtemperature in the range of about 350° F. (177° C.) to about 850° F.(454° C.) selected to perform the desired conversion to reduce oreliminate the undesirable characteristics or components of thehydrocarbonaceous compounds. Further preferred operating conditionsinclude liquid hourly space velocities in the range from about 0.2 hr⁻¹to about 10 hr⁻¹ and hydrogen circulation rates from about 200 standardcubic feet per barrel (SCFB) (35.6 m³ /m³) to about 10,000 SCFB (1778 m³/m³), preferably from about 300 SCFB (53.3 m³ /m³) to about 8000 SCFB(1422 m³ /m³).

The preferred catalytic composite disposed within the hereinabovedescribed hydrogenation zone can be characterized as containing ametallic component having hydrogenation activity, which component iscombined with a suitable refractory inorganic oxide carrier material ofeither synthetic or natural origin. The precise composition and methodof manufacturing the carrier material is not considered essential to thepresent invention. Preferred carrier materials are alumina, silica andmixtures thereof. Suitable metallic components having hydrogenationactivity are those selected from the group comprising the metals ofGroups VI-B and VIII of the Periodic Table, as set forth in the PeriodicTable of the Elements, E. H. Sargent and Company, 1964. Thus, thecatalytic composites may comprise one or more metallic components fromthe group of molybdenum, tungsten, chromium, iron, cobalt, nickel,platinum, iridium, osmium, rhodium, ruthenium, and mixtures thereof. Theconcentration of the catalytically active metallic component, orcomponents, is primarily dependent upon a particular metal as well asthe physical and/or chemical characteristics of the particularhydrocarbon feedstock. For example, the metallic components of GroupVI-B are generally present in an amount within the range of from about 1to about 20 weight percent, the iron-group metals in an amount withinthe range of about 0.2 to about 10 weight percent, whereas the noblemetals of Group VIII are preferably present in an amount within therange of from about 0.1 to about 5 weight percent, all of which arecalculated as if these components existed within the catalytic compositein the elemental state. In addition, any catalyst employed commerciallyfor hydrotreating middle distillate hydrocarbonaceous compounds toremove nitrogen and sulfur should normally function effectively in thehydrogenation zone of the present invention.

The hydrocarbonaceous effluent from the hydrogenation zone is contactedwith an aqueous scrubbing solution and the resulting admixture isadmitted to a separation zone in order to separate a spent aqueousscrubbing solution, a hydrogenated hydrocarbonaceous phase comprisinghydrotreated elution solvent and hydrotreated hydrocarbonaceouscompounds which formerly contaminated the waste water charge stock and ahydrogen-rich gaseous phase. The contact of the hydrocarbonaceouseffluent from the hydrogenation zone with the aqueous scrubbing solutionmay be performed in any convenient manner and is preferably conducted byco-current, in-line mixing which may be promoted by inherent turbulence,mixing orifices or any other suitable mixing means. The aqueousscrubbing solution is preferably introduced in an amount from about 1 toabout 40 volume percent based on the hydrocarbonaceous effluent from thehydrogenation zone. The aqueous scrubbing solution is selected dependingon the characteristics of the hydrocarbonaceous compounds which areentrained in the contaminated waste water charge stock. For example, ifthe hydrocarbonaceous compounds present in the waste water charge stockcomprise halogenated compounds, the aqueous scrubbing solutionpreferably contains a basic compound such as calcium hydroxide,potassium hydroxide or sodium hydroxide in order to neutralize the acidwhich is formed during the hydrogenation of the halogen compounds. Inthe event that the hydrocarbonaceous compound contaminants contain onlysulfur and nitrogen compounds, pure water is a suitable aqueousscrubbing solution. The resulting hydrotreated hydrocarbonaceous phaseis recovered and the hydrogen-rich gaseous phase may be recycled to thehydrogenation zone if desired. In a preferred embodiment of the subjectinvention, at least a portion of the recovered hydrocarbonaceous phaseis recycled as at least a portion of the elution solvent mentionedhereinabove. A portion of the aqueous scrubbing solution recovered inthe separation zone may be recycled to contact the hydrocarbonaceouseffluent from the hydrogenation zone. The spent aqueous scrubbingsolution may be neutralized or otherwise treated to provide a moreenvironmentally acceptable effluent.

In the drawing, the process of the present invention is illustrated bymeans of a simplified flow diagram in which such details as pumps,instrumentation, heat-exchange and heat-recovery circuits, compressors,surge tanks and similar hardware have been deleted as beingnon-essential to an understanding of the techniques involved. The use ofsuch miscellaneous appurtenances are well within the purview of oneskilled in the art.

With reference now to the drawing, an aqueous charge stock contaminatedwith trace quantities of hydrocarbonaceous compounds is introduced intothe process via conduit 1 and is passed via conduit 2, valve 3 andconduit 4 into adsorption zone 5. Alternatively, the contaminated wastewater charge stock is introduced via conduit 6, valve 7, and conduit 8into adsorption zone 9 which is located in parallel with adsorption zone5. An aqueous stream having a reduced concentration of hydrocarbonaceouscompounds is removed from adsorption zone 5 via conduit 10, conduit 11,valve 12, conduit 13 and recovered. In the alternative, an aqueousstream having a reduced concentration of hydrocarbonaceous compounds isremoved from adsorption zone 9 via conduit 14, valve 15, conduit 16,conduit 13 and recovered. In the event adsorption zone 9 is to beregenerated, valves 7 and 15 are closed for isolation and an elutionsolvent is introduced via conduit 17, valve 20, conduit 17, and conduit14 into adsorption zone 9. An elution solvent rich in hydrocarbonaceouscompounds which have been extracted from adsorption zone 9 is removedvia conduit 8, conduit 21, valve 22 and conduit 21 and is introducedinto hydrotreating reaction zone 25. In the event that adsorption zone 5is to be regenerated, valves 3 and 12 are closed for isolation and anelution solvent is introduced via conduit 17, conduit 18, valve 19,conduit 18 and conduit 10 into adsorption zone 5. An elution solventrich in hydrocarbonaceous compounds is removed from adsorption zone 5via conduit 4, conduit 23, valve 24, conduit 23, and conduit 21 andintroduced into hydrotreating reaction zone 25. A hydrogen-rich gaseousstream which is derived in a manner hereinafter described is introducedvia conduit 32 and conduit 21 into hydrotreating reaction zone 25.Make-up hydrogen is introduced via conduit 33, conduit 32 and conduit 21into hydrotreating reaction zone 25. The admixture of elution solventand hydrocarbonaceous contaminants is hydrogenated in hydrotreatingreaction zone 25 in the presence of a hydrogenation catalyst maintainedat hydrogenation conditions as described hereinabove. The resultinghydrotreated elution solvent and hydrocarbonaceous compounds and agaseous phase are removed from hydrotreating reaction zone 25 viaconduit 26 and contacted with an aqueous scrubbing solution introducedvia conduit 27. The resulting mixture is introduced via conduit 26 intohigh pressure separator 28. A hydrogen-rich gaseous phase is removedfrom high pressure separator 28 via conduit 32 and recycled as describedhereinabove. A detoxified hydrocarbonaceous stream comprisinghydrotreated elution solvent is removed from high pressure separator 28via conduit 29 and recovered. At least a portion of the detoxifiedhydrocarbonaceous stream comprising hydrotreated elution solvent isrecycled via conduit 31 to provide at least a portion of the elutionsolvent which is provided via conduit 17. A spent aqueous scrubbingsolution is removed from high pressure separator 28 via conduit 30 andis recovered.

The process of the present invention, is further demonstrated by thefollowing illustrative embodiment. This illustrative embodiment ishowever not presented to unduly limit the process of this invention, butto further illustrate the advantages of the hereinabove describedembodiments. The following data were not obtained by the actualperformance of the present invention, but are considered prospective andreasonably illustrative of the expected performance of the invention.

ILLUSTRATIVE EMBODIMENT

This illustrative embodiment describes the removal of poly chlorinatedbiphenyl (PCB) from an aqueous stream which contains 500 weight PPM ofPCB in an adsorption zone, the subsequent elution of the PCB from anadsorbent contained in the adsorption zone and the conversion of theeluted PCB by hydrotreating to produce innocuous hydrocarbonaceouscompounds.

An aqueous stream of water containing 500 weight PPM of PCB isintroduced into an adsorption zone containing activated carbon particlesat conditions including a temperature of about 100° F. (38° C.), apressure of about 10 psig (69 k Pa gauge), and a liquid hourly spacevelocity of about 10. The resulting aqueous phase is found to containless than 1 PPM of PCB. Another adsorption zone containing activatedcarbon particles which is located in parallel with the hereinabovementioned adsorption zone and is regenerated to remove previouslyadsorbed PCB by contacting the activated carbon containing PCB with anelution solvent comprising heptane, a component of naphtha, atconditions which include a temperature of about 100° F. (38° C.), and apressure of about 10 psig (69 k Pa gauge) for a time sufficient to eluteor remove substantially all of the transient PCB from the activatedcarbon adsorbent. The resulting admixture of elution solvent and PCBremoved from the adsorbent is then introduced together with a gaseoushydrogen-rich stream into a hydrotreating reaction zone loaded with acatalyst comprising alumina, cobalt and molybdenum. The hydrotreatingreaction is conducted with a catalyst peak temperature of 750° F. (399°C.), a pressure of 900 psig (6205 k Pa gauge), a liquid hourly spacevelocity of 1 based on fresh feed and a hydrogen circulation rate of2500 SCFB (444 std m³ /m³). The effluent from the hydrotreating reactionzone is contacted with an aqueous sodium hydroxide solution in an amountof 10 volume percent based on the hydrocarbonaceous effluent from thehydrotreating zone. The admixture of the hydrotreating reaction zoneeffluent and the aqueous scrubbing solution is introduced into aseparation zone to provide a spent aqueous stream and a hydrotreatedelution solvent having less than 1 PPM of PCB.

The foregoing description, drawing and illustrative embodiment clearlyillustrate the advantages encompassed by the process of the presentinvention and the benefits to be afforded with the use thereof.

I claim as my invention:
 1. A process for the removal of trace quantities of hydrocarbonaceous compounds from an aqueous stream which comprises the steps of:(a) contacting said aqueous stream with an adsorbent to remove trace quantities of hydrocarbonaceous compounds from said aqueous stream to provide an aqueous stream having a reduced concentration of hydrocarbonaceous compounds; (b) contacting spent adsorbent which has accumulated said hydrocarbonaceous compounds from said aqueous stream with an elution solvent to remove said hydrocarbonaceous compounds from said spent adsorbent thereby regenerating said adsorbent; (c) contacting said elution solvent in admixture with said hydrocarbonaceous compounds which were removed from said spent adsorbent in step (b) in the presence of hydrogen with a hydrogenation catalyst in a hydrotreating reaction zone; (d) contacting the hydrotreating reaction zone effluent with an aqueous scrubbing solution; (e) introducing a resulting admixture of said reaction zone effluent and said aqueous scrubbing solution into a separation zone to provide a hydrotreated elution solvent and a spent aqueous stream; and (f) recycling at least a portion of said hydrotreated elution solvent from step (e) to provide at least a portion of said elution solvent utilized in step (b).
 2. The process of claim 1 wherein said hydrocarbonaceous compounds comprise hazardous hydrocarbonaceous compounds.
 3. The process of claim 2 wherein said hazardous hydrocarbonaceous compounds are halogenated hydrocarbons or organometallic compounds.
 4. The process of claim 1 wherein said hydrotreating reaction zone is operated at conditions which include a pressure from about 100 psig (689 k Pa gauge) to about 2000 psig (13790 k Pa gauge), a maximum catalyst temperature from about 350° F. (177° C.) to about 850° F. (454° C.) and a hydrogen circulation rate from about 200 SCFB (35.6 std m³ /m³) to about 10,000 SCFB (1778 std m³ /m³).
 5. The process of claim 1 wherein said hydrogenation catalyst comprises a refractory inorganic oxide and at least one metallic compound having hydrogenation activity.
 6. The process of claim 5 wherein said metallic compound is selected from the metals of Groups VI-B and VIII of the Periodic Table.
 7. The process of claim 1 wherein said aqueous scrubbing solution comprises an alkaline compound.
 8. The process of claim 7 wherein said alkaline compound is sodium hydroxide, potassium hydroxide or calcium hydroxide.
 9. The process of claim 1 wherein said adsorbent is silica gel, activated carbon, activated alumina, silica-alumina gel, clay, molecular sieves or admixtures thereof.
 10. The process of claim 1 wherein said contacting conducted in step (a) is performed at conditions which include a pressure from about atmospheric to about 1500 psig (10,342 k Pa gauge) and a temperature from about 32° F. (0° C.) to about 300° F. (149° C.) and a liquid hourly space velocity from about 0.1 hr⁻¹ to about 500 hr⁻¹.
 11. The process of claim 1 wherein the adsorbent regeneration conducted in step (b) is performed at conditions which include a pressure from about atmospheric to about 1500 psig (10,342 k Pa gauge) and a temperature from about 32° F. (0° C.) to about 300° F. (149° C.).
 12. The process of claim 1 wherein said aqueous stream having a reduced hydrocarbonaceous compound concentration is essentially hydrocarbon-free.
 13. The process of claim 1 wherein said elution solvent is naphtha, kerosene, diesel fuel, gas oil or mixtures thereof. 